jetty-http2/http2-hpack/src/main/java/org/eclipse/jetty/http2/hpack/HpackContext.java - gerrit/jetty/org.eclipse.jetty.project - Git at Google

 //
 //  ========================================================================
 //  Copyright (c) 1995-2015 Mort Bay Consulting Pty. Ltd.
 //  ------------------------------------------------------------------------
 //  All rights reserved. This program and the accompanying materials
 //  are made available under the terms of the Eclipse Public License v1.0
 //  and Apache License v2.0 which accompanies this distribution.
 //
 //      The Eclipse Public License is available at
 //      http://www.eclipse.org/legal/epl-v10.html
 //
 //      The Apache License v2.0 is available at
 //      http://www.opensource.org/licenses/apache2.0.php
 //
 //  You may elect to redistribute this code under either of these licenses.
 //  ========================================================================
 //

 package org.eclipse.jetty.http2.hpack;

 import java.nio.ByteBuffer;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Map;
 import java.util.Set;

 import org.eclipse.jetty.http.HttpField;
 import org.eclipse.jetty.http.HttpHeader;
 import org.eclipse.jetty.http.HttpMethod;
 import org.eclipse.jetty.http.HttpScheme;
 import org.eclipse.jetty.util.ArrayQueue;
 import org.eclipse.jetty.util.ArrayTernaryTrie;
 import org.eclipse.jetty.util.StringUtil;
 import org.eclipse.jetty.util.Trie;
 import org.eclipse.jetty.util.log.Log;
 import org.eclipse.jetty.util.log.Logger;


 /* ------------------------------------------------------------ */
 /** HPACK - Header Compression for HTTP/2
  * <p>This class maintains the compression context for a single HTTP/2
  * connection. Specifically it holds the static and dynamic Header Field Tables
  * and the associated sizes and limits.
  * </p>
  * <p>It is compliant with draft 11 of the specification</p>
  */
 public class HpackContext
 {
     public static final Logger LOG = Log.getLogger(HpackContext.class);

     public static final String[][] STATIC_TABLE =
     {
         {null,null},
         /* 1  */ {":authority",null},
         /* 2  */ {":method","GET"},
         /* 3  */ {":method","POST"},
         /* 4  */ {":path","/"},
         /* 5  */ {":path","/index.html"},
         /* 6  */ {":scheme","http"},
         /* 7  */ {":scheme","https"},
         /* 8  */ {":status","200"},
         /* 9  */ {":status","204"},
         /* 10 */ {":status","206"},
         /* 11 */ {":status","304"},
         /* 12 */ {":status","400"},
         /* 13 */ {":status","404"},
         /* 14 */ {":status","500"},
         /* 15 */ {"accept-charset",null},
         /* 16 */ {"accept-encoding","gzip, deflate"},
         /* 17 */ {"accept-language",null},
         /* 18 */ {"accept-ranges",null},
         /* 19 */ {"accept",null},
         /* 20 */ {"access-control-allow-origin",null},
         /* 21 */ {"age",null},
         /* 22 */ {"allow",null},
         /* 23 */ {"authorization",null},
         /* 24 */ {"cache-control",null},
         /* 25 */ {"content-disposition",null},
         /* 26 */ {"content-encoding",null},
         /* 27 */ {"content-language",null},
         /* 28 */ {"content-length",null},
         /* 29 */ {"content-location",null},
         /* 30 */ {"content-range",null},
         /* 31 */ {"content-type",null},
         /* 32 */ {"cookie",null},
         /* 33 */ {"date",null},
         /* 34 */ {"etag",null},
         /* 35 */ {"expect",null},
         /* 36 */ {"expires",null},
         /* 37 */ {"from",null},
         /* 38 */ {"host",null},
         /* 39 */ {"if-match",null},
         /* 40 */ {"if-modified-since",null},
         /* 41 */ {"if-none-match",null},
         /* 42 */ {"if-range",null},
         /* 43 */ {"if-unmodified-since",null},
         /* 44 */ {"last-modified",null},
         /* 45 */ {"link",null},
         /* 46 */ {"location",null},
         /* 47 */ {"max-forwards",null},
         /* 48 */ {"proxy-authenticate",null},
         /* 49 */ {"proxy-authorization",null},
         /* 50 */ {"range",null},
         /* 51 */ {"referer",null},
         /* 52 */ {"refresh",null},
         /* 53 */ {"retry-after",null},
         /* 54 */ {"server",null},
         /* 55 */ {"set-cookie",null},
         /* 56 */ {"strict-transport-security",null},
         /* 57 */ {"transfer-encoding",null},
         /* 58 */ {"user-agent",null},
         /* 59 */ {"vary",null},
         /* 60 */ {"via",null},
         /* 61 */ {"www-authenticate",null},
     };

     private static final Map<HttpField,Entry> __staticFieldMap = new HashMap<>();
     private static final Trie<StaticEntry> __staticNameMap = new ArrayTernaryTrie<>(true,512);
     private static final StaticEntry[] __staticTableByHeader = new StaticEntry[HttpHeader.UNKNOWN.ordinal()];
     private static final StaticEntry[] __staticTable=new StaticEntry[STATIC_TABLE.length];
     static
     {
         Set<String> added = new HashSet<>();
         for (int i=1;i<STATIC_TABLE.length;i++)
         {
             StaticEntry entry=null;

             String name  = STATIC_TABLE[i][0];
             String value = STATIC_TABLE[i][1];
             HttpHeader header = HttpHeader.CACHE.get(name);
             if (header!=null && value!=null)
             {
                 switch (header)
                 {
                     case C_METHOD:
                     {

                         HttpMethod method = HttpMethod.CACHE.get(value);
                         if (method!=null)
                             entry=new StaticEntry(i,new StaticTableHttpField(header,name,value,method));
                         break;
                     }

                     case C_SCHEME:
                     {

                         HttpScheme scheme = HttpScheme.CACHE.get(value);
                         if (scheme!=null)
                             entry=new StaticEntry(i,new StaticTableHttpField(header,name,value,scheme));
                         break;
                     }

                     case C_STATUS:
                     {
                         entry=new StaticEntry(i,new StaticTableHttpField(header,name,value,Integer.valueOf(value)));
                         break;
                     }

                     default:
                         break;
                 }
             }

             if (entry==null)
                 entry=new StaticEntry(i,header==null?new HttpField(STATIC_TABLE[i][0],value):new HttpField(header,name,value));


             __staticTable[i]=entry;

             if (entry._field.getValue()!=null)
                 __staticFieldMap.put(entry._field,entry);

             if (!added.contains(entry._field.getName()))
             {
                 added.add(entry._field.getName());
                 __staticNameMap.put(entry._field.getName(),entry);
                 if (__staticNameMap.get(entry._field.getName())==null)
                     throw new IllegalStateException("name trie too small");
             }
         }

         for (HttpHeader h : HttpHeader.values())
         {
             StaticEntry entry = __staticNameMap.get(h.asString());
             if (entry!=null)
                 __staticTableByHeader[h.ordinal()]=entry;
         }
     }

     private int _maxDynamicTableSizeInBytes;
     private int _dynamicTableSizeInBytes;
     private final DynamicTable _dynamicTable;
     private final Map<HttpField,Entry> _fieldMap = new HashMap<>();
     private final Map<String,Entry> _nameMap = new HashMap<>();

     HpackContext(int maxDynamicTableSize)
     {
         _maxDynamicTableSizeInBytes=maxDynamicTableSize;
         int guesstimateEntries = 10+maxDynamicTableSize/(32+10+10);
         _dynamicTable=new DynamicTable(guesstimateEntries,guesstimateEntries+10);
         if (LOG.isDebugEnabled())
             LOG.debug(String.format("HdrTbl[%x] created max=%d",hashCode(),maxDynamicTableSize));
     }

     public void resize(int newMaxDynamicTableSize)
     {
         if (LOG.isDebugEnabled())
             LOG.debug(String.format("HdrTbl[%x] resized max=%d->%d",hashCode(),_maxDynamicTableSizeInBytes,newMaxDynamicTableSize));
         _maxDynamicTableSizeInBytes=newMaxDynamicTableSize;
         int guesstimateEntries = 10+newMaxDynamicTableSize/(32+10+10);
         evict();
         _dynamicTable.resizeUnsafe(guesstimateEntries);
     }

     public Entry get(HttpField field)
     {
         Entry entry = _fieldMap.get(field);
         if (entry==null)
             entry=__staticFieldMap.get(field);
         return entry;
     }

     public Entry get(String name)
     {
         Entry entry = __staticNameMap.get(name);
         if (entry!=null)
             return entry;
         return _nameMap.get(StringUtil.asciiToLowerCase(name));
     }

     public Entry get(int index)
     {
         if (index<__staticTable.length)
             return __staticTable[index];

         int d=_dynamicTable.size()-index+__staticTable.length-1;

         if (d>=0)
             return _dynamicTable.getUnsafe(d);
         return null;
     }

     public Entry get(HttpHeader header)
     {
         Entry e = __staticTableByHeader[header.ordinal()];
         if (e==null)
             return get(header.asString());
         return e;
     }

     public static Entry getStatic(HttpHeader header)
     {
         return __staticTableByHeader[header.ordinal()];
     }

     public Entry add(HttpField field)
     {
         int slot=_dynamicTable.getNextSlotUnsafe();
         Entry entry=new Entry(slot,field);
         int size = entry.getSize();
         if (size>_maxDynamicTableSizeInBytes)
         {
             if (LOG.isDebugEnabled())
                 LOG.debug(String.format("HdrTbl[%x] !added size %d>%d",hashCode(),size,_maxDynamicTableSizeInBytes));
             return null;
         }
         _dynamicTableSizeInBytes+=size;
         _dynamicTable.addUnsafe(entry);
         _fieldMap.put(field,entry);
         _nameMap.put(StringUtil.asciiToLowerCase(field.getName()),entry);

         if (LOG.isDebugEnabled())
             LOG.debug(String.format("HdrTbl[%x] added %s",hashCode(),entry));
         evict();
         return entry;
     }

     /**
      * @return Current dynamic table size in entries
      */
     public int size()
     {
         return _dynamicTable.size();
     }

     /**
      * @return Current Dynamic table size in Octets
      */
     public int getDynamicTableSize()
     {
         return _dynamicTableSizeInBytes;
     }

     /**
      * @return Max Dynamic table size in Octets
      */
     public int getMaxDynamicTableSize()
     {
         return _maxDynamicTableSizeInBytes;
     }

     public int index(Entry entry)
     {
         if (entry._slot<0)
             return 0;
         if (entry.isStatic())
             return entry._slot;

         return _dynamicTable.index(entry)+__staticTable.length-1;
     }

     public static int staticIndex(HttpHeader header)
     {
         if (header==null)
             return 0;
         Entry entry=__staticNameMap.get(header.asString());
         if (entry==null)
             return 0;
         return entry.getSlot();
     }

     private void evict()
     {
         while (_dynamicTableSizeInBytes>_maxDynamicTableSizeInBytes)
         {
             Entry entry = _dynamicTable.pollUnsafe();
             if (LOG.isDebugEnabled())
                 LOG.debug(String.format("HdrTbl[%x] evict %s",hashCode(),entry));
             _dynamicTableSizeInBytes-=entry.getSize();
             entry._slot=-1;
             _fieldMap.remove(entry.getHttpField());
             String lc=StringUtil.asciiToLowerCase(entry.getHttpField().getName());
             if (entry==_nameMap.get(lc))
                 _nameMap.remove(lc);
         }
         if (LOG.isDebugEnabled())
             LOG.debug(String.format("HdrTbl[%x] entries=%d, size=%d, max=%d",hashCode(),_dynamicTable.size(),_dynamicTableSizeInBytes,_maxDynamicTableSizeInBytes));
     }

     @Override
     public String toString()
     {
         return String.format("HpackContext@%x{entries=%d,size=%d,max=%d}",hashCode(),_dynamicTable.size(),_dynamicTableSizeInBytes,_maxDynamicTableSizeInBytes);
     }


     /* ------------------------------------------------------------ */
     /**
      */
     private class DynamicTable extends ArrayQueue<HpackContext.Entry>
     {
         /* ------------------------------------------------------------ */
         /**
          * @param initCapacity
          * @param growBy
          */
         private DynamicTable(int initCapacity, int growBy)
         {
             super(initCapacity,growBy);
         }

         /* ------------------------------------------------------------ */
         /**
          * @see org.eclipse.jetty.util.ArrayQueue#growUnsafe()
          */
         @Override
         protected void resizeUnsafe(int newCapacity)
         {
             // Relay on super.growUnsafe to pack all entries 0 to _nextSlot
             super.resizeUnsafe(newCapacity);
             for (int s=0;s<_nextSlot;s++)
                 ((Entry)_elements[s])._slot=s;
         }

         /* ------------------------------------------------------------ */
         /**
          * @see org.eclipse.jetty.util.ArrayQueue#enqueue(java.lang.Object)
          */
         @Override
         public boolean enqueue(Entry e)
         {
             return super.enqueue(e);
         }

         /* ------------------------------------------------------------ */
         /**
          * @see org.eclipse.jetty.util.ArrayQueue#dequeue()
          */
         @Override
         public Entry dequeue()
         {
             return super.dequeue();
         }

         /* ------------------------------------------------------------ */
         /**
          * @param entry
          * @return
          */
         private int index(Entry entry)
         {
             return entry._slot>=_nextE?_size-entry._slot+_nextE:_nextSlot-entry._slot;
         }

     }


     /* ------------------------------------------------------------ */
     /* ------------------------------------------------------------ */
     /* ------------------------------------------------------------ */
     public static class Entry
     {
         final HttpField _field;
         int _slot;

         Entry()
         {
             _slot=0;
             _field=null;
         }

         Entry(int index,String name, String value)
         {
             _slot=index;
             _field=new HttpField(name,value);
         }

         Entry(int slot, HttpField field)
         {
             _slot=slot;
             _field=field;
         }

         public int getSize()
         {
             return 32+_field.getName().length()+_field.getValue().length();
         }

         public HttpField getHttpField()
         {
             return _field;
         }

         public boolean isStatic()
         {
             return false;
         }

         public byte[] getStaticHuffmanValue()
         {
             return null;
         }

         public int getSlot()
         {
             return _slot;
         }

         public String toString()
         {
             return String.format("{%s,%d,%s,%x}",isStatic()?"S":"D",_slot,_field,hashCode());
         }
     }

     public static class StaticEntry extends Entry
     {
         private final byte[] _huffmanValue;
         private final byte _encodedField;

         StaticEntry(int index,HttpField field)
         {
             super(index,field);
             String value = field.getValue();
             if (value!=null && value.length()>0)
             {
                 int huffmanLen = Huffman.octetsNeeded(value);
                 int lenLen = NBitInteger.octectsNeeded(7,huffmanLen);
                 _huffmanValue = new byte[1+lenLen+huffmanLen];
                 ByteBuffer buffer = ByteBuffer.wrap(_huffmanValue);

                 // Indicate Huffman
                 buffer.put((byte)0x80);
                 // Add huffman length
                 NBitInteger.encode(buffer,7,huffmanLen);
                 // Encode value
                 Huffman.encode(buffer,value);
             }
             else
                 _huffmanValue=null;

             _encodedField=(byte)(0x80|index);
         }

         @Override
         public boolean isStatic()
         {
             return true;
         }

         @Override
         public byte[] getStaticHuffmanValue()
         {
             return _huffmanValue;
         }

         public byte getEncodedField()
         {
             return _encodedField;
         }
     }


 }
	//
	// ========================================================================
	// Copyright (c) 1995-2015 Mort Bay Consulting Pty. Ltd.
	// ------------------------------------------------------------------------
	// All rights reserved. This program and the accompanying materials
	// are made available under the terms of the Eclipse Public License v1.0
	// and Apache License v2.0 which accompanies this distribution.
	//
	// The Eclipse Public License is available at
	// http://www.eclipse.org/legal/epl-v10.html
	//
	// The Apache License v2.0 is available at
	// http://www.opensource.org/licenses/apache2.0.php
	//
	// You may elect to redistribute this code under either of these licenses.
	// ========================================================================
	//

	package org.eclipse.jetty.http2.hpack;

	import java.nio.ByteBuffer;
	import java.util.HashMap;
	import java.util.HashSet;
	import java.util.Map;
	import java.util.Set;

	import org.eclipse.jetty.http.HttpField;
	import org.eclipse.jetty.http.HttpHeader;
	import org.eclipse.jetty.http.HttpMethod;
	import org.eclipse.jetty.http.HttpScheme;
	import org.eclipse.jetty.util.ArrayQueue;
	import org.eclipse.jetty.util.ArrayTernaryTrie;
	import org.eclipse.jetty.util.StringUtil;
	import org.eclipse.jetty.util.Trie;
	import org.eclipse.jetty.util.log.Log;
	import org.eclipse.jetty.util.log.Logger;


	/* ------------------------------------------------------------ */
	/** HPACK - Header Compression for HTTP/2
	* <p>This class maintains the compression context for a single HTTP/2
	* connection. Specifically it holds the static and dynamic Header Field Tables
	* and the associated sizes and limits.
	* </p>
	* <p>It is compliant with draft 11 of the specification</p>
	*/
	public class HpackContext
	{
	public static final Logger LOG = Log.getLogger(HpackContext.class);

	public static final String[][] STATIC_TABLE =
	{
	{null,null},
	/* 1 */ {":authority",null},
	/* 2 */ {":method","GET"},
	/* 3 */ {":method","POST"},
	/* 4 */ {":path","/"},
	/* 5 */ {":path","/index.html"},
	/* 6 */ {":scheme","http"},
	/* 7 */ {":scheme","https"},
	/* 8 */ {":status","200"},
	/* 9 */ {":status","204"},
	/* 10 */ {":status","206"},
	/* 11 */ {":status","304"},
	/* 12 */ {":status","400"},
	/* 13 */ {":status","404"},
	/* 14 */ {":status","500"},
	/* 15 */ {"accept-charset",null},
	/* 16 */ {"accept-encoding","gzip, deflate"},
	/* 17 */ {"accept-language",null},
	/* 18 */ {"accept-ranges",null},
	/* 19 */ {"accept",null},
	/* 20 */ {"access-control-allow-origin",null},
	/* 21 */ {"age",null},
	/* 22 */ {"allow",null},
	/* 23 */ {"authorization",null},
	/* 24 */ {"cache-control",null},
	/* 25 */ {"content-disposition",null},
	/* 26 */ {"content-encoding",null},
	/* 27 */ {"content-language",null},
	/* 28 */ {"content-length",null},
	/* 29 */ {"content-location",null},
	/* 30 */ {"content-range",null},
	/* 31 */ {"content-type",null},
	/* 32 */ {"cookie",null},
	/* 33 */ {"date",null},
	/* 34 */ {"etag",null},
	/* 35 */ {"expect",null},
	/* 36 */ {"expires",null},
	/* 37 */ {"from",null},
	/* 38 */ {"host",null},
	/* 39 */ {"if-match",null},
	/* 40 */ {"if-modified-since",null},
	/* 41 */ {"if-none-match",null},
	/* 42 */ {"if-range",null},
	/* 43 */ {"if-unmodified-since",null},
	/* 44 */ {"last-modified",null},
	/* 45 */ {"link",null},
	/* 46 */ {"location",null},
	/* 47 */ {"max-forwards",null},
	/* 48 */ {"proxy-authenticate",null},
	/* 49 */ {"proxy-authorization",null},
	/* 50 */ {"range",null},
	/* 51 */ {"referer",null},
	/* 52 */ {"refresh",null},
	/* 53 */ {"retry-after",null},
	/* 54 */ {"server",null},
	/* 55 */ {"set-cookie",null},
	/* 56 */ {"strict-transport-security",null},
	/* 57 */ {"transfer-encoding",null},
	/* 58 */ {"user-agent",null},
	/* 59 */ {"vary",null},
	/* 60 */ {"via",null},
	/* 61 */ {"www-authenticate",null},
	};

	private static final Map<HttpField,Entry> __staticFieldMap = new HashMap<>();
	private static final Trie<StaticEntry> __staticNameMap = new ArrayTernaryTrie<>(true,512);
	private static final StaticEntry[] __staticTableByHeader = new StaticEntry[HttpHeader.UNKNOWN.ordinal()];
	private static final StaticEntry[] __staticTable=new StaticEntry[STATIC_TABLE.length];
	static
	{
	Set<String> added = new HashSet<>();
	for (int i=1;i<STATIC_TABLE.length;i++)
	{
	StaticEntry entry=null;

	String name = STATIC_TABLE[i][0];
	String value = STATIC_TABLE[i][1];
	HttpHeader header = HttpHeader.CACHE.get(name);
	if (header!=null && value!=null)
	{
	switch (header)
	{
	case C_METHOD:
	{

	HttpMethod method = HttpMethod.CACHE.get(value);
	if (method!=null)
	entry=new StaticEntry(i,new StaticTableHttpField(header,name,value,method));
	break;
	}

	case C_SCHEME:
	{

	HttpScheme scheme = HttpScheme.CACHE.get(value);
	if (scheme!=null)
	entry=new StaticEntry(i,new StaticTableHttpField(header,name,value,scheme));
	break;
	}

	case C_STATUS:
	{
	entry=new StaticEntry(i,new StaticTableHttpField(header,name,value,Integer.valueOf(value)));
	break;
	}

	default:
	break;
	}
	}

	if (entry==null)
	entry=new StaticEntry(i,header==null?new HttpField(STATIC_TABLE[i][0],value):new HttpField(header,name,value));


	__staticTable[i]=entry;

	if (entry._field.getValue()!=null)
	__staticFieldMap.put(entry._field,entry);

	if (!added.contains(entry._field.getName()))
	{
	added.add(entry._field.getName());
	__staticNameMap.put(entry._field.getName(),entry);
	if (__staticNameMap.get(entry._field.getName())==null)
	throw new IllegalStateException("name trie too small");
	}
	}

	for (HttpHeader h : HttpHeader.values())
	{
	StaticEntry entry = __staticNameMap.get(h.asString());
	if (entry!=null)
	__staticTableByHeader[h.ordinal()]=entry;
	}
	}

	private int _maxDynamicTableSizeInBytes;
	private int _dynamicTableSizeInBytes;
	private final DynamicTable _dynamicTable;
	private final Map<HttpField,Entry> _fieldMap = new HashMap<>();
	private final Map<String,Entry> _nameMap = new HashMap<>();

	HpackContext(int maxDynamicTableSize)
	{
	_maxDynamicTableSizeInBytes=maxDynamicTableSize;
	int guesstimateEntries = 10+maxDynamicTableSize/(32+10+10);
	_dynamicTable=new DynamicTable(guesstimateEntries,guesstimateEntries+10);
	if (LOG.isDebugEnabled())
	LOG.debug(String.format("HdrTbl[%x] created max=%d",hashCode(),maxDynamicTableSize));
	}

	public void resize(int newMaxDynamicTableSize)
	{
	if (LOG.isDebugEnabled())
	LOG.debug(String.format("HdrTbl[%x] resized max=%d->%d",hashCode(),_maxDynamicTableSizeInBytes,newMaxDynamicTableSize));
	_maxDynamicTableSizeInBytes=newMaxDynamicTableSize;
	int guesstimateEntries = 10+newMaxDynamicTableSize/(32+10+10);
	evict();
	_dynamicTable.resizeUnsafe(guesstimateEntries);
	}

	public Entry get(HttpField field)
	{
	Entry entry = _fieldMap.get(field);
	if (entry==null)
	entry=__staticFieldMap.get(field);
	return entry;
	}

	public Entry get(String name)
	{
	Entry entry = __staticNameMap.get(name);
	if (entry!=null)
	return entry;
	return _nameMap.get(StringUtil.asciiToLowerCase(name));
	}

	public Entry get(int index)
	{
	if (index<__staticTable.length)
	return __staticTable[index];

	int d=_dynamicTable.size()-index+__staticTable.length-1;

	if (d>=0)
	return _dynamicTable.getUnsafe(d);
	return null;
	}

	public Entry get(HttpHeader header)
	{
	Entry e = __staticTableByHeader[header.ordinal()];
	if (e==null)
	return get(header.asString());
	return e;
	}

	public static Entry getStatic(HttpHeader header)
	{
	return __staticTableByHeader[header.ordinal()];
	}

	public Entry add(HttpField field)
	{
	int slot=_dynamicTable.getNextSlotUnsafe();
	Entry entry=new Entry(slot,field);
	int size = entry.getSize();
	if (size>_maxDynamicTableSizeInBytes)
	{
	if (LOG.isDebugEnabled())
	LOG.debug(String.format("HdrTbl[%x] !added size %d>%d",hashCode(),size,_maxDynamicTableSizeInBytes));
	return null;
	}
	_dynamicTableSizeInBytes+=size;
	_dynamicTable.addUnsafe(entry);
	_fieldMap.put(field,entry);
	_nameMap.put(StringUtil.asciiToLowerCase(field.getName()),entry);

	if (LOG.isDebugEnabled())
	LOG.debug(String.format("HdrTbl[%x] added %s",hashCode(),entry));
	evict();
	return entry;
	}

	/**
	* @return Current dynamic table size in entries
	*/
	public int size()
	{
	return _dynamicTable.size();
	}

	/**
	* @return Current Dynamic table size in Octets
	*/
	public int getDynamicTableSize()
	{
	return _dynamicTableSizeInBytes;
	}

	/**
	* @return Max Dynamic table size in Octets
	*/
	public int getMaxDynamicTableSize()
	{
	return _maxDynamicTableSizeInBytes;
	}

	public int index(Entry entry)
	{
	if (entry._slot<0)
	return 0;
	if (entry.isStatic())
	return entry._slot;

	return _dynamicTable.index(entry)+__staticTable.length-1;
	}

	public static int staticIndex(HttpHeader header)
	{
	if (header==null)
	return 0;
	Entry entry=__staticNameMap.get(header.asString());
	if (entry==null)
	return 0;
	return entry.getSlot();
	}

	private void evict()
	{
	while (_dynamicTableSizeInBytes>_maxDynamicTableSizeInBytes)
	{
	Entry entry = _dynamicTable.pollUnsafe();
	if (LOG.isDebugEnabled())
	LOG.debug(String.format("HdrTbl[%x] evict %s",hashCode(),entry));
	_dynamicTableSizeInBytes-=entry.getSize();
	entry._slot=-1;
	_fieldMap.remove(entry.getHttpField());
	String lc=StringUtil.asciiToLowerCase(entry.getHttpField().getName());
	if (entry==_nameMap.get(lc))
	_nameMap.remove(lc);
	}
	if (LOG.isDebugEnabled())
	LOG.debug(String.format("HdrTbl[%x] entries=%d, size=%d, max=%d",hashCode(),_dynamicTable.size(),_dynamicTableSizeInBytes,_maxDynamicTableSizeInBytes));
	}

	@Override
	public String toString()
	{
	return String.format("HpackContext@%x{entries=%d,size=%d,max=%d}",hashCode(),_dynamicTable.size(),_dynamicTableSizeInBytes,_maxDynamicTableSizeInBytes);
	}



	/* ------------------------------------------------------------ */
	/**
	*/
	private class DynamicTable extends ArrayQueue<HpackContext.Entry>
	{
	/* ------------------------------------------------------------ */
	/**
	* @param initCapacity
	* @param growBy
	*/
	private DynamicTable(int initCapacity, int growBy)
	{
	super(initCapacity,growBy);
	}

	/* ------------------------------------------------------------ */
	/**
	* @see org.eclipse.jetty.util.ArrayQueue#growUnsafe()
	*/
	@Override
	protected void resizeUnsafe(int newCapacity)
	{
	// Relay on super.growUnsafe to pack all entries 0 to _nextSlot
	super.resizeUnsafe(newCapacity);
	for (int s=0;s<_nextSlot;s++)
	((Entry)_elements[s])._slot=s;
	}

	/* ------------------------------------------------------------ */
	/**
	* @see org.eclipse.jetty.util.ArrayQueue#enqueue(java.lang.Object)
	*/
	@Override
	public boolean enqueue(Entry e)
	{
	return super.enqueue(e);
	}

	/* ------------------------------------------------------------ */
	/**
	* @see org.eclipse.jetty.util.ArrayQueue#dequeue()
	*/
	@Override
	public Entry dequeue()
	{
	return super.dequeue();
	}

	/* ------------------------------------------------------------ */
	/**
	* @param entry
	* @return
	*/
	private int index(Entry entry)
	{
	return entry._slot>=_nextE?_size-entry._slot+_nextE:_nextSlot-entry._slot;
	}

	}



	/* ------------------------------------------------------------ */
	/* ------------------------------------------------------------ */
	/* ------------------------------------------------------------ */
	public static class Entry
	{
	final HttpField _field;
	int _slot;

	Entry()
	{
	_slot=0;
	_field=null;
	}

	Entry(int index,String name, String value)
	{
	_slot=index;
	_field=new HttpField(name,value);
	}

	Entry(int slot, HttpField field)
	{
	_slot=slot;
	_field=field;
	}

	public int getSize()
	{
	return 32+_field.getName().length()+_field.getValue().length();
	}

	public HttpField getHttpField()
	{
	return _field;
	}

	public boolean isStatic()
	{
	return false;
	}

	public byte[] getStaticHuffmanValue()
	{
	return null;
	}

	public int getSlot()
	{
	return _slot;
	}

	public String toString()
	{
	return String.format("{%s,%d,%s,%x}",isStatic()?"S":"D",_slot,_field,hashCode());
	}
	}

	public static class StaticEntry extends Entry
	{
	private final byte[] _huffmanValue;
	private final byte _encodedField;

	StaticEntry(int index,HttpField field)
	{
	super(index,field);
	String value = field.getValue();
	if (value!=null && value.length()>0)
	{
	int huffmanLen = Huffman.octetsNeeded(value);
	int lenLen = NBitInteger.octectsNeeded(7,huffmanLen);
	_huffmanValue = new byte[1+lenLen+huffmanLen];
	ByteBuffer buffer = ByteBuffer.wrap(_huffmanValue);

	// Indicate Huffman
	buffer.put((byte)0x80);
	// Add huffman length
	NBitInteger.encode(buffer,7,huffmanLen);
	// Encode value
	Huffman.encode(buffer,value);
	}
	else
	_huffmanValue=null;

	_encodedField=(byte)(0x80\|index);
	}

	@Override
	public boolean isStatic()
	{
	return true;
	}

	@Override
	public byte[] getStaticHuffmanValue()
	{
	return _huffmanValue;
	}

	public byte getEncodedField()
	{
	return _encodedField;
	}
	}


	}